JPH01244345A - Neutron measuring apparatus - Google Patents
Neutron measuring apparatusInfo
- Publication number
- JPH01244345A JPH01244345A JP6977088A JP6977088A JPH01244345A JP H01244345 A JPH01244345 A JP H01244345A JP 6977088 A JP6977088 A JP 6977088A JP 6977088 A JP6977088 A JP 6977088A JP H01244345 A JPH01244345 A JP H01244345A
- Authority
- JP
- Japan
- Prior art keywords
- neutron
- neutrons
- measuring chamber
- measurement
- measurement chamber
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000004992 fission Effects 0.000 claims abstract description 8
- 238000005259 measurement Methods 0.000 claims description 62
- 239000004698 Polyethylene Substances 0.000 abstract description 12
- -1 polyethylene Polymers 0.000 abstract description 12
- 229920000573 polyethylene Polymers 0.000 abstract description 12
- 239000000463 material Substances 0.000 abstract description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 6
- 239000012188 paraffin wax Substances 0.000 abstract description 5
- 238000004519 manufacturing process Methods 0.000 abstract description 3
- 238000006243 chemical reaction Methods 0.000 abstract description 2
- 239000000446 fuel Substances 0.000 abstract description 2
- 230000035939 shock Effects 0.000 abstract 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 9
- 229910002804 graphite Inorganic materials 0.000 description 9
- 239000010439 graphite Substances 0.000 description 9
- 238000001514 detection method Methods 0.000 description 8
- 238000010521 absorption reaction Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 239000003758 nuclear fuel Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 239000002901 radioactive waste Substances 0.000 description 3
- 230000007423 decrease Effects 0.000 description 2
- 239000011358 absorbing material Substances 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000005253 cladding Methods 0.000 description 1
- 239000012634 fragment Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000012958 reprocessing Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Landscapes
- Analysing Materials By The Use Of Radiation (AREA)
Abstract
Description
【発明の詳細な説明】
〔発明の目的〕
（産業上の利用分野）
本発明は放射性廃棄物等の測定試料に含まれる核燃料物
質量を分析するために、その測定試料に中性子を照射し
て即発中性子を計数する中性子測定装置に関する。[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention is a method of irradiating a measurement sample such as radioactive waste with neutrons in order to analyze the amount of nuclear fuel material contained in the measurement sample. This invention relates to a neutron measurement device that counts prompt neutrons.
（従来の技術）
一般に、原子力発電所で生成する放射性廃棄物は、核燃
料物質を含む可能性のあるものは、その含有量を分析す
るために、測定装置により分析される必要がある。(Prior Art) Generally, radioactive waste generated at a nuclear power plant that may contain nuclear fuel materials needs to be analyzed using a measuring device in order to analyze the content thereof.
第２図はその測定装置の一例で従来の即発中性子測定法
による中性子測定装置を示す構成図である。FIG. 2 is an example of such a measuring device, and is a block diagram showing a neutron measuring device using a conventional prompt neutron measuring method.
第２図において、測定室１はポリエチレン２およびグラ
ファイト３の２種類の中性子減速材から構成される。測
定室１内側に配設されるグラファイト３は密度１．６ｇ
／ｃｃ、吸収断面積Σａ＝３゜２ Ｘ １０−’ａｓ−
’、散乱断面積ΣＳ ＝ ０．３８５ＣｒＲ−’であり
、測定室１外側に配設されるポリエチレン２は密度０．
９２ｇ／ＣＣ１吸収断面積Σａ＝０．０２６３３ 、
散乱断面積ΣＳ＝３．２０Ｃ＃＋−１であ−す
る。In FIG. 2, the measurement chamber 1 is composed of two types of neutron moderators, polyethylene 2 and graphite 3. The graphite 3 placed inside the measurement chamber 1 has a density of 1.6g.
/cc, absorption cross section Σa=3゜2 X 10-'as-
', scattering cross section ΣS = 0.385CrR-', and the polyethylene 2 disposed outside the measurement chamber 1 has a density of 0.
92g/CC1 absorption cross section Σa=0.02633,
The scattering cross section ΣS=3.20C#+-1.
このように構成される測定ｖ１内に中性子発生管ヘッド
４が備えられ、その中性子発生管ヘッド４から測定室１
内へパルス状に高速中性子が照射される。照射された高
速中性子は測定室１内を進んでグラフフィト３に達し、
このグラフフィト３で減速されて熱中性子となる。生成
した熱中性子はその後散乱断面積が大きいポリエチレン
２により反射されて測定室１内へ戻る。この場合、グラ
ファイト３およびポリエチレン２の吸収断面積が比較的
小さいため生成した熱中性子の減少が抑制される。A neutron generating tube head 4 is provided in the measurement v1 configured in this manner, and the measurement chamber 1 is connected from the neutron generating tube head 4 to the measuring chamber 1.
Fast neutrons are irradiated inward in a pulsed manner. The irradiated fast neutrons proceed through the measurement chamber 1 and reach the graphite 3.
It is decelerated by this graphite 3 and becomes a thermal neutron. The generated thermal neutrons are then reflected by the polyethylene 2 having a large scattering cross section and returned into the measurement chamber 1. In this case, since the absorption cross-sections of graphite 3 and polyethylene 2 are relatively small, the decrease in generated thermal neutrons is suppressed.
その後、熱中性子は測定試料５に達し、その熱中性子に
より測定試料５中に含まれる核分裂性物質が核分裂を起
こして高速中性子を放出する。放出された高速中性子は
測定室１中を進んでグラフフィト３に達し、このグラフ
ァイト３を通過した後、その高速成分が中性子検出装置
６に検出される。Thereafter, the thermal neutrons reach the measurement sample 5, and the fissile material contained in the measurement sample 5 undergoes nuclear fission due to the thermal neutrons, releasing fast neutrons. The emitted fast neutrons advance through the measurement chamber 1 and reach the graphite 3, and after passing through the graphite 3, their high speed components are detected by the neutron detection device 6.
（発明が解決しようとする課題）
従来の中性子測定装置は測定室１がポリエチレン２およ
びグラファイト３の２種類の中性子減速材から構成され
ている。しかしながら、これらの中性子減速材のうちグ
ラファイトは■吸水性があってその水分により減速効果
が変化し、装置自体の分析性能に影響がある、■機械工
作、組立などがポリエチレン等と比較して複雑かつ困難
である、■衝撃力に対する強度が不充分であり、ひび割
れ等が入りやすいという問題がある。(Problems to be Solved by the Invention) In the conventional neutron measurement device, the measurement chamber 1 is composed of two types of neutron moderators, polyethylene 2 and graphite 3. However, among these neutron moderators, graphite: ■ Has water absorption properties, and its moderating effect changes depending on the moisture content, which affects the analytical performance of the device itself. ■ Machining and assembly are more complicated than polyethylene, etc. (1) The strength against impact force is insufficient, and cracks are likely to occur.
本発明は上記の事情を考慮してなされたもので、装置の
分析性能を維持することができるとともに、製作が容易
で！！７カにも強い測定室を有する中性子測定装置を提
供することを目的とする。The present invention was made in consideration of the above circumstances, and it is possible to maintain the analytical performance of the device, and it is easy to manufacture! ! The purpose of the present invention is to provide a neutron measurement device having a measurement chamber that is strong against 7 forces.
（課題を解決するための手段）
本発明は、中性子減速材からなる測定室と、この測定室
内に収容される測定試料と、上記測定室内へ高速中性子
をパルス状に照）Ｊする中性子発生器と、前記測定試料
から核分裂により放射される高速中性子を検出する複数
の中性子検出装置とが備えられた中性子測定装置におい
て、前記測定室は１種類の中性子減速材から構成された
ものである。(Means for Solving the Problems) The present invention provides a measurement chamber made of a neutron moderator, a measurement sample accommodated in the measurement chamber, and a neutron generator that pulses high-speed neutrons into the measurement chamber. and a plurality of neutron detection devices for detecting fast neutrons emitted by nuclear fission from the measurement sample, wherein the measurement chamber is composed of one type of neutron moderator.
（作用）
中性子発生器から照射された高速中性子は測定室を構成
する１種類の中性子減速材により減速されるとともに反
射されて熱中性子として測定室内に戻る。そして、この
熱中性子により測定試料中の核分裂性物質が核分裂を起
こして高速中性子を放出し、この高速中性子が中性子検
出装置に検出される。(Operation) Fast neutrons irradiated from the neutron generator are decelerated by one type of neutron moderator that constitutes the measurement chamber, and are reflected and returned to the measurement chamber as thermal neutrons. These thermal neutrons cause the fissile material in the measurement sample to undergo nuclear fission and emit fast neutrons, which are detected by a neutron detection device.
前記測定室は１種類の中性子減速材から構成されるから
製作が容易で衝撃力にも強く、かつ装置の分析性能を損
うこともない。Since the measurement chamber is composed of one type of neutron moderator, it is easy to manufacture, strong against impact forces, and does not impair the analytical performance of the apparatus.
（実施例）
本発明に係る中性子測定装置の一実施例を第１図を用い
て説明する。(Example) An example of a neutron measuring device according to the present invention will be described with reference to FIG.
中性子測定装置は、中性子減速材７からなる測定室１と
、この測定室１内に収容される測定試料５と、上記測定
室１内へ高速中性子をパルス状に照射する中性子発生器
８と、前記測定試料５から核分裂により放射される高速
中性子を検出する複数の中性子検出装置６とが備えられ
る。The neutron measurement device includes a measurement chamber 1 made of a neutron moderator 7, a measurement sample 5 housed in the measurement chamber 1, a neutron generator 8 that irradiates the measurement chamber 1 with high-speed neutrons in a pulsed manner, A plurality of neutron detection devices 6 are provided to detect fast neutrons emitted from the measurement sample 5 by nuclear fission.
測定室１を構成する中性子減速材７としては散乱断面積
（ΣＳ）が大きい水素を含む物質としてポリエチレン（
（ＣＨＣＨ２）ｎ）、水（）」２０）、パラフィン（Ｃ
ｎｌ−１）のうちいずれか２ｎ＋２
１種類が用いられる。ポリエチレンおよびパラフィンは
加熱することにより容易に測鎖室１を形成することがで
きる。また、水はアルミニウム製等の容器内に貯留する
ことにより容易に測定室１を構成することができる。さ
らに、ポリエチレンＪ３よびパラフィンは吸湿性を有せ
ず、また水も異物が混入しない限り減速効果が安定して
いる。これらの中性子減速材は中性子を測定室１内に封
じ込めるため、少なくとも３ ｃｍ以上の厚さが確保さ
れる。As the neutron moderator 7 constituting the measurement chamber 1, polyethylene (
(CHCH2)n), water (20), paraffin (C
nl-1), one type of 2n+2 is used. The chain measuring chamber 1 can be easily formed by heating polyethylene and paraffin. Furthermore, the measurement chamber 1 can be easily configured by storing water in a container made of aluminum or the like. Furthermore, polyethylene J3 and paraffin do not have hygroscopic properties, and water has a stable deceleration effect unless foreign matter is mixed in. These neutron moderators are required to have a thickness of at least 3 cm in order to confine neutrons within the measurement chamber 1.
測定試料５は主として放射性廃棄物であり、例えば核燃
料の再処理工程で生じる燃料被覆管の破片（ハル：１Ｉ
ｕｌｌ）等が代表的なものである。また、中性子発生器
８は測定室１内に中性子発生管ヘッド４を有し、この中
性子発生管ヘッド４から測定室１内へパルス状に高速中
性子を照射するようになっている。The measurement sample 5 is mainly radioactive waste, such as fuel cladding fragments (hull: 1I) produced in the nuclear fuel reprocessing process.
(ull) etc. are typical examples. Further, the neutron generator 8 has a neutron generation tube head 4 in the measurement chamber 1, and is configured to irradiate high-speed neutrons into the measurement chamber 1 from the neutron generation tube head 4 in a pulsed manner.
中性子検出装置６は複数基設けられ、測定試料５を取り
囲んで配設される。各中性子検出装置６はカドミウム等
の中性子吸収材９に囲まれたポリエチレン等の中性子減
速材１０内に熱中性子検出器１１が備えられる。熱中性
子検出器１１としては例えば３１（ｅカウンタ、１０ｓ
ラインドカウンタ、フィッションチェンバが用いられる
。A plurality of neutron detection devices 6 are provided and are arranged to surround the measurement sample 5. Each neutron detection device 6 includes a thermal neutron detector 11 within a neutron moderator 10 such as polyethylene surrounded by a neutron absorbing material 9 such as cadmium. As the thermal neutron detector 11, for example, 31 (e counter, 10s
Lined counters and fission chambers are used.
次に、上記実施例の作用について説明する。Next, the operation of the above embodiment will be explained.
中性子発生管ヘッド４から照射された１ ４ＭｅＶの高
速中性子は測定室１内を進み中性子減速材７に達する。Fast neutrons of 14 MeV irradiated from the neutron generating tube head 4 travel within the measurement chamber 1 and reach the neutron moderator 7.
中性子減速材７は散乱断面積が大きいため、中性子減速
材７に達した高速中性子は中性子減速材７の表面やある
程度透過したところに衝突し、数１０μｓｅｃの半減期
で減速されて熱中性子となり、この熱中性子は測定室１
内に封じ込められる。Since the neutron moderator 7 has a large scattering cross section, the fast neutrons that reach the neutron moderator 7 collide with the surface of the neutron moderator 7 or a place where they have passed through to some extent, and are decelerated with a half-life of several tens of microseconds and become thermal neutrons. This thermal neutron is in the measurement chamber 1
Contained within.
生成した熱中性子は、その後測定室１内で数１００μｓ
ｅｃの半減期で減少してゆき、この熱中性子により測定
試料５に含まれる核分裂性物質が核分裂反応を起こし、
即発中性子を発生する。発生した即発中性子は測定室１
内を進み、その高速成分が中性子検出装置６により検出
される。そして、検出された中性子計数は測定試料５に
含まれる核分裂性物質量と比例関係にあるため、その中
性子計数から核燃料物質量を評価することができる。The generated thermal neutrons then remain in the measurement chamber 1 for several hundred μs.
It decreases during the half-life of ec, and the fissile material contained in the measurement sample 5 causes a fission reaction due to these thermal neutrons.
Generates prompt neutrons. The prompt neutrons generated are transferred to measurement room 1.
The high-speed component is detected by the neutron detection device 6. Since the detected neutron count is proportional to the amount of fissile material contained in the measurement sample 5, the amount of nuclear fuel material can be evaluated from the neutron count.
上記実施例においては測定室１を構成する中性子減速材
７としてポリエチレン、水、パラフィンのうらいずれか
１種類を用いているから、容易に測定室１を製作できる
とともに、衝撃力にも強い測定室１を構成することがで
きる。また、これらの物質は減速効果が安定しており装
置の分析性能を維持することができる。In the above embodiment, since one of polyethylene, water, and paraffin is used as the neutron moderator 7 constituting the measurement chamber 1, the measurement chamber 1 can be easily manufactured, and the measurement chamber is strong against impact forces. 1 can be configured. In addition, these substances have a stable deceleration effect and can maintain the analytical performance of the device.
本発明に係る中性子測定装置は測定室が１種類の中性子
減速材から構成されたから、極めて容易に測定室を製作
できるとともに、衝撃力にも強い測定室を構成すること
ができるという効果がある。In the neutron measurement device according to the present invention, since the measurement chamber is made of one type of neutron moderator, the measurement chamber can be manufactured very easily, and the measurement chamber can be constructed to be strong against impact forces.
第１図は本発明に係る中性子測定装置の一実施例を示す
構成図、第２図は従来の中性子測定装置を示す構成図で
ある。
１・・・測定室、４・・・中性子発生管ヘッド、５・・
・測定試料、６・・・中性子検出装置。
出願人代理人 波 多 野 久羊１ｇFIG. 1 is a block diagram showing an embodiment of a neutron measurement device according to the present invention, and FIG. 2 is a block diagram showing a conventional neutron measurement device. 1...Measurement chamber, 4...Neutron generating tube head, 5...
-Measurement sample, 6...neutron detection device. Applicant's agent Hisashi Hatano 1g
Claims (1)
れる測定試料と、上記測定室内へ高速中性子をパルス状
に照射する中性子発生器と、前記測定試料から核分裂に
より放射される高速中性子を検出する複数の中性子検出
装置とが備えられた中性子測定装置において、前記測定
室は１種類の中性子減速材から構成されたことを特徴と
する中性子測定装置。A measurement chamber made of a neutron moderator, a measurement sample housed in this measurement chamber, a neutron generator that irradiates pulsed fast neutrons into the measurement chamber, and detects fast neutrons emitted from the measurement sample by nuclear fission. A neutron measuring device comprising a plurality of neutron detecting devices, wherein the measuring chamber is made of one type of neutron moderator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6977088A JPH01244345A (en) | 1988-03-25 | 1988-03-25 | Neutron measuring apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6977088A JPH01244345A (en) | 1988-03-25 | 1988-03-25 | Neutron measuring apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01244345A true JPH01244345A (en) | 1989-09-28 |
Family
ID=13412361
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6977088A Pending JPH01244345A (en) | 1988-03-25 | 1988-03-25 | Neutron measuring apparatus |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01244345A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5828069A (en) * | 1994-10-19 | 1998-10-27 | Commissariat A L'energie Atomique | Irradiation and/or counting enclosure for neutron detection analysis |
| JP2002541491A (en) * | 1999-04-08 | 2002-12-03 | コミツサリア タ レネルジー アトミーク | Radioactive material analysis process and analyzer |
| JP2009281878A (en) * | 2008-05-22 | 2009-12-03 | Japan Atomic Energy Agency | Detector bank for nondestructive measuring device and nondestructive measuring device |
| CN112219115A (en) * | 2017-12-29 | 2021-01-12 | 俄罗斯国家原子能公司 | Device for actively monitoring fissionable substances |
-
1988
- 1988-03-25 JP JP6977088A patent/JPH01244345A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5828069A (en) * | 1994-10-19 | 1998-10-27 | Commissariat A L'energie Atomique | Irradiation and/or counting enclosure for neutron detection analysis |
| JP2002541491A (en) * | 1999-04-08 | 2002-12-03 | コミツサリア タ レネルジー アトミーク | Radioactive material analysis process and analyzer |
| JP4854116B2 (en) * | 1999-04-08 | 2012-01-18 | コミッサリア ア レネルジー アトミーク エ オ ゼネルジ ザルタナテイヴ | Radioactive substance analysis process and analysis equipment |
| JP2009281878A (en) * | 2008-05-22 | 2009-12-03 | Japan Atomic Energy Agency | Detector bank for nondestructive measuring device and nondestructive measuring device |
| CN112219115A (en) * | 2017-12-29 | 2021-01-12 | 俄罗斯国家原子能公司 | Device for actively monitoring fissionable substances |
| JP2021512278A (en) * | 2017-12-29 | 2021-05-13 | ステート・アトミック・エナジー・コーポレーション・ロスアトム・オン・ビハーフ・オブ・ザ・ロシアン・フェデレーションＳｔａｔｅ Ａｔｏｍｉｃ Ｅｎｅｒｇｙ Ｃｏｒｐｏｒａｔｉｏｎ ‘Ｒｏｓａｔｏｍ’ Ｏｎ Ｂｅｈａｌｆ Ｏｆ Ｔｈｅ Ｒｕｓｓｉａｎ Ｆｅｄｅｒａｔｉｏｎ | Operation management device for fissile material |
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